July 17, 2007: Cambridge, MA
Distributed at the International Development
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Tech Brief: Efficient small wind power, without turbines
Humdinger Wind Energy, LLC has successfully demonstrated the
first efficient turbine-less wind generator on the small scale.
Shawn Frayne, founder of Humdinger, explains, “For the past
thousand years, wind power has centered around rotation.
Rotating dutch wind mills for pounding grain, rotating sail designs
for pumping water, and most recently rotating turbine-based
generators for creating electricity. These approaches work well
for large-scale applications. However, on the small-scale, rotating
systems are very inefficient -- close to 1% efficiency. That’s why
there is nothing on the wind power market in the milliwatt through
the 100-watt range. Can you imagine if there was nothing in the
sub 100-watt range for solar! The reason for this hole is that most
research groups are stuck on shrinking
turbines, but they are finding that
doesn’t work so well.”
Humdinger is taking a different
approach. If traditional turbines
are like spinning airplane wings,
Humdinger’s technology is more akin
to the vibrating bow of a stringed
instrument.
The new technology is known as
a “windbelt”TM. The invention was
originally developed to provide
very low-cost electricity to off-grid,
rural areas of Haiti, with other
applications coming more recently.
The next generation of wind power?
A prototype designed for powering wireless sensors, white LEDs,
cell phones, and radios, in 10mph wind.
“The original goal was to make a very small-scale wind power
and WLED system that could compete with kerosene lighting,”
Frayne recalls. “Basically, I wanted to power several white LEDs
with a system that was under US$10. Surprisingly, turbine-based
generators couldn’t meet the economic and manufacturability
benchmarks. It turns out that’s a fundamental limitation for
turbines, they don’t scale down well. And that’s what forced the
development of the windbelt, these difficult constraints.”
Humdinger’s new wind technology works by capitalizing on an
effect known as aeroelastic flutter, most famously exhibited in
the Tacoma Narrows bridge collapse. Typically, and for obvious
reasons, this flutter instability is something that engineers aspire
to eliminate from a bridge, or a wind turbine.
Humdinger estimates that the unit cost of production-level
quantities of the technology will be between US$1-5, for a
windbelt that is scaled to power a couple of high-intensity white
LEDs or charge a cell phone. Field trials are planned in the U.S.
(for wireless sensor applications) and in Haiti (rural lighting, radio,
cell phone charging) for early 2008.
Tacoma Narrows Bridge, 1940
However, Humdinger has shown that this flutter phenomenon
can be reformed to help harvest the wind. In laboratory tests,
small, flat windbelt prototypes have produced 30-40 mW in a 10
mph wind, for hundreds of hours. At the scales and wind speeds
concerned, this translates into the windbelt technology being
10X more efficient than the published state of the art in microturbines. The windbelt has also demonstrated its ability to run
radios, power transmissions from wireless sensors, re-charge cell
phones, and light white LEDs, in low wind speeds of 5-14 mph.
Moreover, this new wind power technology could conceivably
be manufactured anywhere in the world. “There aren’t any
specialized materials or manufacturing processes required to
make windbelt generators. All of the components are off-theshelf,” Frayne explains. “It’s not like photovoltaic technologies
that required the development of large silicon processing plants
before anyone could even think of mass-manufacturing solar
cells. Because of this unique advantage, I think in three to
five years windbelts of the scale needed for rural lighting will
produced within Haiti and in other developing countries. When
the manufacturing process is fully worked out, I don’t think it will
be any more complicated a process to make a windbelt than it is
to print a newspaper.”
Humdinger Wind Energy, LLC is based out of Honolulu, HI and
Mountain View, CA. Humdinger is a company founded on the
principle that the key technologies of the next fifty years will
be invented in developing countries. Harder problems, better
inventions.
Any questions and comments should be directed to:
Shawn Frayne, [email protected]. tel. 650.279.0109
Legal Notice:
The windbelt technology has U.S. and PCT patents pending. The intent is to license the
intellectual property within the US, Germany, and Japan in the new sector of “consumer” level wind
power – using wind power to run applications such as wireless sensor nodes. This will generate
the funds necessary to travel the much longer road of building an international business for the
windbelt in developing countries.
However, because of the one-nation nature of patents, anyone working outside of these patent
pending countries is free to refine, use, manufacture, and sell the technology.
For the work that IDDS is focused on, this means the technology is open source and free to
replicate, improve, sell, etc. in virtually all developing countries.